Comment 1 for bug 355522

Yes, this happens when I try to mount an external drive, by clicking the drive in "Computer" in Nautilus.

And I found this https://bugzilla.redhat.com/show_bug.cgi?id=492242 Bug 492242 - Mounting NTFS or HFS drives displays seemingly pointless message "An operation is already pending"

"Description of problem:
As I was testing the nouveau driver using the Test Day 2009-03-25 Live CD, I
found that attempting to mount my HFS+ or NTFS internal partitions displayed
this error message:

Unable to mount location
DBus error org.gtk.Private.RemoteVolumeMonitor.Failed: An operation is already
pending

However, after a second or two the partitions mounted as usual.

Version-Release number of selected component (if applicable):
Test Day 2009-03-25 Live CD

How reproducible:
Always

Steps to Reproduce:
1. Select Places > Computer from the menu
2. Attempt to mount HFS+ or NTFS volumes

Actual results:
Error message: "DBus error org.gtk.Private.RemoteVolumeMonitor.Failed: An
operation is already pending" as the volume is being mounted

Expected results:
Volumes mount without the error message being displayed

Additional info:
I was running off of a CD, not USB media- maybe the operation was just taking
longer than expected because of the slow read speeds?
"